Pilot-operable hydraulic valve



New 11, 1969 F. TOWN 3,477,465

PILOT OPERABLE HYDRAULIC VALVE Filed May 22, 1967 3 Sheets-Sheet l Nov. 11, 1969 F. TOWN PILOT-OPERABLE HYDRAULIC VALVE 3 Sheets-Sheet 2 Filed May 22, 1967 Nova-11, 1969- F.- TOWN 3,477,455

PILOT OPERABLE HYDRAULI C VALVE Filed May 22, 1967 3 Sheets-Sheet 5 3 INVENTOR= FRANK TOWN ATT'YS United States Patent 3,477,465 PILOT-OPERABLE HYDRAULIC VALVE Frank Town, Burton Joyce, England, assignor to W. E. & F. Dobson Limited Filed May 22, 1967, Ser. No. 640,280 Claims priority, application Great Britain, May 25, 1966, 23,301/66 Int. Cl. F15b 13/06 US. Cl. 137-596.18 3 Claims ABSTRACT OF THE DISCLOSURE In or for a hydraulic circuit of a hydraulic mine roof support system, hydraulic valves which are pilot-operated for extending conveyor-advancing jacks and in which pressure and exhaust valve means after operation by pilot signals are maintained operated by action of the main pressure fluid in predetermined passages against the valve members, thereby to relieve the pilot system for other uses, with enlarged pistons operable by the main fluid pressure under control of main control valves for acting on the pressure and exhaust valves to reset them.

This invention is for improvements in or relating to a pilot-operable hydraulic valve primarily for inclusion with a main control valve in the hydraulic circuit of a hydraulic mine roof support connected to a working face conveyor by an advancing hydraulic jack, the pilot-operable valve being connected to pressure and exhaust lines and to the piston end of the advancing hydraulic jack and having pressure and return valve means operable by a pilot system to open a pressure passage to the piston end of the advancing cylinder so that the pressure fluid extends the advancing hydraulic jack Which carries the conveyor with it.

In order that the conveyor is advanced by this means with the usual snaking action, there is one auxiliary pilot operated valve for each conveyor-advancing hydraulic jack of a plurality of supports. These valves are operated in groups, and because of this the pilot system has had to be in use to hold the valves operated for undesirably long periods during which the pilot system is prevented from use for any other purpose. Furthermore in instances of the pilot system being of electric type, there is an element of danger created by the electric connections to the auxiliary valves being live for undesirably long periods.

An object of the invention is to provide pilot-operable hydraulic valves of such improved construction that they do not require use of the pilot system for undesirably long periods.

The invention provides a pilot-operable hydraulic valve in which pressure and exhaust valve means are pilotoperable in one direction for opening the valve to pressure fluid feed, passage means associated with the pressure and exhaust valve means are adapted for guiding the pressure of fluid to act on the valve means for maintaining the latter operated independently of the pilot operation, and enlarged piston means is adapted for operation by fluid pressure to reset the valve means.

The invention also provides, for a hydraulic step-bystep service-operating system, a pilot-operable valve for instigating operation of a service and having a first pressure port for direct connection to a pressure fluid feed, a second pressure port for connection through a control valve to a pressure fluid feed, a service port for connection to the service, and exhaust port for connection to exhaust, pressure and exhaust valve means, pilot-operable piston means adapting the valve means to be pilot-operable in one direction for opening the first pressure port 3,477,465 Patented Nov. 11, 1969 to the service port and closing the service port to exhaust, a pressure passage extending between the first pressure port and the service port adapting the valve means to be maintainable operated in said direction by a first fluid pressure in said pressure passage, and large area piston means associated with said second pressure port adapting the valve means to be operable in return direction by a second fluid pressure similar to the first fluid pressure and which can be applied when required through the second pressure port to the piston means by operation of the control valve. Conveniently the valve means comprises a pressure valve and a separate exhaust valve, the pilot-operable piston means comprises a first pilot-operable piston associated with the pressure valve and a second pilot-operable piston associated with the exhaust valve, and the large area piston means comprises a first large area piston associated with the pressure valve and a second large area piston associated with the exhaust valve. Conveniently also the pressure valve includes a pressure slide valve member, the exhaust valve includes a similar and parallel exhaust slide valve member, the first and second pilot-operable pistons are axially aligned with the respective slide valve members at one end thereof, and the first and second large area pistons are axially aligned with the respective slide valve members at the other end thereof. In one arrangement the pressure and exhaust valve members and associated pistons are accommodated in parallel pressure and exhaust slideways respectively, and there is in the pressure slideway a mounting block slidable mounting the pressure valve member, and in the exhaust slideway a mounting block slidably mounting the exhaust valve member and having through openings and a valve seat opening. Conveniently the pressure passage extending between the first pressure port and the service port comprises a pressure valve chamber accommodating the head of the pressure slide valve member, a valve-seat-opening in a side of the pressure valve chamber, an exhaust valve chamber in which the head of the exhaust slide valve member is accommodated, and a pressure duct which inter-communicates between the pressure valve-seat-opening and the exhaust valve chamber.

In one application of the invention the service port is connected to the piston end of an advancing hydraulic jack connected between a mine roof support, having hydraulic props, and a conveyor, and the second pressure port is connected to the supports main control valve and to the annulus side of the hydraulic props and the advancing hydraulic jack. Conveniently the valve has in combination therewith a plurality of similar valves similarly connected to similar mine roof supports and advancing hydraulic jacks, and jointly connected to a common pilot system.

The invention also provides long wall mining apparatus comprising a plurality of mine roof supports, having hydraulic props under control of main hydraulic control valves, and a conveyor adapted for relative advancements by advancing hydraulic jacks connected between them and a plurality of auxiliary pilot-operable hydraulic valves in the hydraulic circuit, and wherein these valves have pressure and exhaust valve members operable from a pilot system for pressure fluid to pass to the piston ends of the advancing hydraulic jacks for advancing the conveyor, fluid chambers for the valve members in which the pressure fluid acts on the valve members to maintain them operated independently of the pilot system, and reset pistons of greater eflective cross sectional areas than those of the valve members and operable for returning the valve members by fluid pressure applied to the reset pistons at the same time as to the annulus sides of the advancing hydraulic jacks and the hydraulic props by subsequent operation of the main control valves.

The above and other features of the invention set out in the appended claims are incorporated in the arrangement, which will be hereinafter particularly described as a specific embodiment with reference to the accompanying drawings in which:

FIGURE 1 is a general side view of a hydraulic mine roof support connected by a hydraulic circuit to an enlarged sectional view of an auxiliary pilot-operated hydraulic valve according to the invention.

FIGURE 2 is a similar view to FIGURE 1 showing the auxiliary valve operated.

FIGURE 3 is a general diagrammatic plan view showing a series of mine roof supports in plan relationship with a working face conveyor.

Referring first to FIGURE 3, the hydraulic mine roof supports 1 to 16 are all of a type having four hydraulic props indicated by the centre lines CL and two of which are indicated in FIGURES 1 and 2 at 17 and 18. Each support also has a roof plate such as 19, FIGURES 1 and 2, a pair of cantilevers such as 20 pivoted to the head plate 19, a pair of further hydraulic props such as 21 under the cantilevers 20, and bases such as 22 whereat the supports incorporate horizontal conveyor-advancing hydraulic jacks such as 23 and the rams 23a of which are connected by links such as 24 to spill plates 25 of a working face conveyor 26.

Although FIGURE 3 shows that each of the supports incorporates an advancing hydraulic jack, by which the supports can be advanced relatively to the conveyor, only a selection of the hydraulic jacks may be operated for advance of the conveyor relatively to the supports.

Referring to FIGURE 1 each support is provided with a known type of 4-way hydraulic main control valve 27 which is connected to hydraulic pressure and return lines and is also connected by line L to the lower piston ends of the props and by line L1 to the upper annulus ends of the props.

The line L1 is also connected by line L2 to the annulus end of the advancing hydraulic jack cylinder 23b, this arrangement being so that operation of the main control valve 27 in the known manner to admit pressure fluid to line L will cause the props to extend and become set with the head plates 19 and cantilevers 20 supporting the roof, and with the line L1 open to exhaust for return of fluid from the upper annulus ends of the props. With the valve 27 further operated in known manner to open line L1 to pressure this causes release of the head plates 19 and cantilevers 20 from the roof and contraction of the props, while the line L is open to exhaust so that fluid from the lower piston'ends of the props goes to exhaust.

At the same time that line L1 is open to pressure line L2 is also open to pressure which causes contraction of the advancing hydraulic jack 23 whereby the release of the props is immediately followed by contraction of the hydraulic jack 23 to advance the support relatively to the stationary conveyor.

To provide for advance of the conveyor, after the main control valve 27 has been operated to set the props, there is provided an auxiliary pilot-operated hydraulic valve such as 28 for each of those advancing hydraulic jacks 23 which are required to be operated for advancing the conveyor.

Each auxiliary valve 28 comprises a suitable valve block in which there is a first pressure port 30 connected to a first pressure fluid feed, a service port 31 connected to the service which in this instance is the piston end of the cylinder 23b, and an exhaust port 33 connected to exhaust.

A slide valve member 37 is slidable in a mounting 38 in a pressure passage 29 with sealing rings 39, 40, and having an end valve head 41 for co-operation with a valve seat opening 34 at one side of a pressure valve chamber 410. In an exhaust passage 32 is a slide valve member 42 slidable in a mounting 43 with suitable sealing O ring 44, and having an end valve head 45 for co-operating with a valve seat opening 36 at the end of through openings 36a in the mounting 43.

It is to be noted, for reasons hereinafter to be given, that the slide valve members 37, 42 are disposed in parallel with their heads at like ends thereof but oppositely directed to co-operate with their valve openings 34, 36.

For operating the valve members 37, 42 ther is provided at the valve head ends of the valve members 37, 42, pilot operated pistons 46, 47 slidable in bearings 48, 49 with sealing 0 rings 50, 51 and disposed co-axially with the respective valve members 37, 42. The pistons 46, 47 project into an end chamber 52 which communicates via a connection 53 to a pilot power source as indicated by line L4.

This pilot system may be of hydraulic form or it may be of electric form operating a solenoid which in turn is adapted to cause the hydraulic pulses to be admitted at the connection 53.

At the other end of the valve member 37 there is a large area piston 54 with suitable O ring 55 and slidable in bearings 56, and at the equivalent end of the valve member 42 there is a large area piston 57 slidable in bearing 58 with suitable sealing O ring 59. The bearings communicate with an adjacent end chamber 60 which communicates by a second pressure port 61 to a line L5 extending to the main control valve 27 and to the annular ends of the props and the advancing hydraulic jack.

There also extends between the first pressure port 30 and the service port 31, a pressure passage which is formed by the valve chamber 41a accommodating the head 41 of the pressure valve member 37, the valve-seatopening 34, in the side of the pressure valve chamber 41a, an exhaust valve chamber 32a in which the head 45 of the exhaust valve member 42 is accommodated, and a pressure duct 35 which inter-communicates between the pressure valve-seat-opening 34 and the exhaust valve chamber 320.

When it is required for the conveyor to be advanced it is necessary that the particular mine roof supports connected with the pushing operation, 'be staked to the roof, and in this position, line L will be pressurized and lines L1 and L5 will be open to exhaust. Thus when the conveyor is to be advanced by operation of a group of hydraulic jacks 23 which are required to advance a section of the conveyor, the pilot-operated valves 28 associated with these hydraulic jacks 23 are all operated simultaneously by the pilot system. Each pilot-operated valve operates by a hydraulic signal which can be of very short duration from the line L4 entering the connection 53 and acting in the chamber 52 to operate the pistons 46, 47 which in turn thrust against the heads 41, 45 of the valve member 37, 42 and displaces these members, together with the large area pistons 54, 57 from the position shown in FIGURE 1 towards the left to the position shown in FIGURE 2.

This causes the valve head 45 to close the valve-seatopening 36 whereby the piston end of the cylinder 23b is closed to the exhaust port 33. It also causes the valve head 41 to open the valve-seat-opening 34 thereby opening the first pressure port 30, via the pressure valve chamber 41a, the valve-seat-opening 34, the communicating duct 35, and the exhaust valve chamber 32a, to the service port 31 and via line L3 to the piston end of the cylinder 23b. By this means pressure fluid passes to the piston end of the cylinder 23b to extend the hydraulic jacks 23 which consequently advances the conveyor 26 as shown in FIGURE 2.

Since for this purpose the pressure fluid passes through the pressure valve chambers 41a and 32a at the right hand side of the valve heads 41, 45 in FIGURE 2, the pressure fluid also functions to hold the valve members 37, 42 in their operated positions in substitution for the operation of the pistons 46, 47 by the pilot system.

Consequently the pilot system can then be employed for any other purpose desired.

The valve members 37 and 42 are thus maintained operated by the fluid pressure until the group of hydraulic jacks 23 have all fully operated under control of their respective pilot-operated valves which have all been operated simultaneously. In other words the group of pilotoperated valves are maintained operated by the pressure fluid until section of the conveyor such as shown inclined in FIGURE 3 has been advanced into a position aligned with the next adjacent previously advanced section.

When the conveyor section has been advanced the mine roof supports may be released singly from the roof and advanced to their new position adjacent to the conveyor. Before this stage, the pilot signal will have been removed from all the pilot-operated valves in the batch, but as described, main fluid pressure will be holding the valves in the actuated position, and the rams will continue pushing until the condition of each separate pilot-operated valve is reversed by action of releasing the particular mine roof support from the roof.

This is accomplished when the main control valve 27 is operated to open the fluid pressure feed to line L1, and to open line L to exhaust, thereby to cause lowering of the roof plate 19 from the roof. Fluid pressure from line L1 will also act, via line L5 and the second pressure port 61, in the chamber 60 to apply pressure to the large area pistons 54, 57.

Due to overbalance of the eflective cross sectional areas of the pistons 54, 57 and the valve members 37, 42, the pressure acting'on the piston 54 will operate it to return the valve member 37 from the position of FIG- URE 2 to the position of FIGURE 1 so as to close the valve seat opening 34, and fluid pressure will be held in the chamber 29 behind the valve head 41. Pressure acting on the piston 57 operates it to return the valve member 42 so as to open the valve seat opening 36.

Consequently the piston end of the cylinder 23b will be open to exhaust, the fluid pressure acting from line L1 via line L2 in the annulus end of the cylinder 23b will retract the ram 23a. This will, in turn, pull the mine roof support up to the conveyor.

It will be noted that when the support has been moved fully forward, and the valve 27 has been operated to reset the support to the roof, the lines L1, L5 and the second pressure port 61 will be open to exhaust, but the valve member 37 will remain in its closed position due to the fluid pressure, held in the pressure chamber 29, acting against the rear of the valve head 41.

These operations occur singly until the supports of the whole batch have been moved forward to their new position.

What I claim is:

1. A fluid latch valve comprising a housing forming parallel pressure and exhaust chambers and pressure and exhaust valve seatings thereon respectively, pressure and exhaust valve members in said chambers respectively adapted for valve opening and closing movements on and oil? said seatings respectively in respectively opposite directions, pilot fluid operable means mounted in said housing for moving said pressure and exhaust valve members into respective valve opening and closing positions, a fluid pressure port communicating with said pressure chamber in the region of said pressure valve member, an exhaust port and a service port communicating with said exhaust chamber on opposite sides of said exhaust valve member, means forming a transverse passage through said housing from said fluid pressure port to said service port and passed said pressure valve member in pressure valve open position and passed said exhaust valve members in exhaust valve closed position for fluid pressure to maintain said pressure and exhaust valve members thus actuated with said serviceport open to said fluid pressure port and closed to said exhaust port, and working fluid operable means mounted in said housing for re-setting said pressure and exhaust valve members into pressure valve closing and exhaust valve opening positions respectively for blocking off said fluid pressure port from said service port and opening the latter to exhaust.

2. A valve as claimed in claim 1 wherein said pilot fluid operable means comprises pilot pistons in one end of said chambers, said housing being formed with a pilot fluid port, and said working fluid operable means comprises large diameter pistons in the other end of said chambers, said housing being formed with a working fluid pressure port.

3. A fluid control latch valve comprising a housing forming parallel pressure and exhaust chambers, a pilot fluid port in a first end of said housing communicating with a first end of said chambers, a service outlet port in a second end of said housing communicating with a second end of said chambers, pressure and exhaust pilot pistons in which first end of said pressure and exhaust chambers respectively, large diameter pressure and exhaust re-setting pistons in said second end of said pressure and exhaust chambers respectively, a pressure fluid inlet port in said housing communicating with said pressure chamber between said pilot and re-setting pistons, a pressure slide valve member mounted in said pressure chamber between said pilot and re-setting pistons and having a pressure valve head opposed to said pressure pilot piston, a seating for said pressure slide valve member between said pressure fluid inlet port. and said pressure pilot piston, a communication passage between said chamber at the opposite side of said seating to said pressure fluid inlet port, a service outlet port in said housing communicating with said exhaust chamber opposite said communication passage, an exhaust port in said housing communicating with said exhaust chamber adjacent said large diameter exhaust r e-setting piston, an exhaust slide valve member in said exhaust chamber be tween said exhaust pilot and re-setting pistons and having an exhaust valve head opposed to said exhaust pilot piston, and a sleeve member secured in said exhaust chamber having an inner sleeve portion mounting said exhaust slide valve member and an outer sleeve portion forming a seating between said exhaust valve head and said large diameter exhaust re-setting piston, whereby said pilot pistons can be pilot fluid operated for unseating said pressure valve member to communicate said pressure inlet port with said service outlet port and for simultaneously seating said exhaust slide valve member to cut oil said service outlet port from said exhaust port, said slide valve members can be maintained thus operated by fluid pressure passing through said communication passage, and said large diameter pistons can be operated by fluid pressure through said service inlet port for re-setting the valve.

References Cited UNITED STATES PATENTS 2,362,339 11/1944 Armington 137-59648 2,584,890 2/1952 Leonard 25 1-63 .4 XR 2,836,196 5/1958 Gunn 137---625.64 2,998,026 8/1961 Becker l37-596.14 3,244,193 4/1966 Loveless 137-4546 HENRY T. KLINKSIEK, Primary Examiner 

